1,620 research outputs found

    Gravitational energy and radiation of a charged black hole

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    We analyze the energy configuration of a charged black hole in the TeleparallelFramework of General Relativity. We obtain the energy-momentum tensor of the gravitationalfield in a stationary frame, and we calculate its contribution to the total energyof the system. We study the same gravitational field measured by an accelerated frameand we analyze how the energy-momentum tensor is transformed. We found that in theaccelerated frame, a Poyinting-like flux appears for the gravitational field but not for theelectromagnetic field.Instituto Argentino de Radioastronom铆aFacultad de Ciencias Astron贸micas y Geof铆sica

    Automatic Categorization of Medical Documents

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    The main objective of this thesis is to propose a categorizing model for medical documents,called HiMeD Model. The HiMeD Model is based on the principle that we denominatedhierarchical correlation of specialized terms, in which a medical concept, to be used in anautomatic categorization process, can always be represented by terms, where these termsare linked up in a hierarchical path. This hierarchical linking can contain components thatallow the determination of these categories ordered by the degree of relevance of theadopted concept. The use of this principle allows us to isolate the categorization tasks fromthe unnecessary influence of terms not belonging to the medical vocabulary of referenceand of the straight calculation of the term-weight in the information retrieval process usedby the classic models. The concepts developed here were used in several experiments thatdemonstrated the quality of the proposed model. These experiments are another importantcontribution of this work. Finally, a tool for automatic coding of medical documents wasimplemented based on the components of our model, thus demonstrating its technologicalcapacity in building automatic categorization tools. This tool, called MedCode, was used inexperiments carried out with the help of medical coding specialists, and its use improvedthe precision of the automatic coding of medical documents. This improvement is largelydue to the interactive and visual characteristics of the prototype, which allowed thespecialists to modify the coding environment, to select the type of processing algorithm,and to modify other document processing options.Sociedad Argentina de Inform谩tica e Investigaci贸n Operativ

    Inconsistency within the Everett Interpretation of Quantum Mechanics

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    De las muchas interpretaciones de la mec谩nica cu谩ntica (MC), pocas han sido tan divulgadas como la de Everett. Esta formulaci贸n se supone realista y libre de los problemas que aquejan a la interpretaci贸n de Copenhague. En el presente trabajo, mostramos los problemas sem谩ntico-ontol贸gicos que implican las formulaciones actuales de esta interpretaci贸n y discutimos el problema que presenta con respecto a las cantidades conservadas y las simetr铆as subyacentes al modelo de espacio-tiempo adoptado. Concluimos que en sus expresiones usuales, la teor铆a de Everett es inconsistente.Perhaps the most exotic interpretation of quantum mechanics is the so-called Everett interpretation. It was first conceived as an overcoming proposal to Copenhagen formulation of QM, free of the problems of the latter and with a realistic approach. In this paper, we show the several semantic and ontological problems in the current formulations of this interpretation, and we discuss the critical problem of the conserved quantities and the assumptions on the space-time symmetries in the theory. We conclude that Everett interpretation and its many modern reformulations are inconsistent.Facultad de Ciencias ExactasFacultad de Ciencias Astron贸micas y Geof铆sicasInstituto Argentino de Radioastronom铆